Forbidden Donut

(CNN) -- Two gunmen opened fire at Fort Hood in Texas on Thursday, killing seven people and wounding between 12 and 15 others, officials said.

One of the shooters has been apprehended, Fort Hood spokesman Sgt. Maj. Jamie Posten told CNN.

"At this point we're looking for the other shooter," Posten said. Asked for a description, he said, "we're trying to develop that information."

President Obama has been informed of the incident, Press Secretary Robert Gibbs told reporters.

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Fort Hood was asking people on post to stay away from windows, CNN affiliate KXXV said. The incident took place at the sports dome, now known as the soldier readiness area, the station reported.

FBI agents are headed to the scene to assist, said Erik Vasys, spokesman for the FBI office in San Antonio. He had no other details.

On the Fort Hood Web site, the word "closed" is posted with the statement, "Effective immediately, Fort Hood is closed. Organizations/units are instructed to execute a 100 percent accountability of all personnel."

Fort Hood is the Army's largest U.S. post, with about 40,000 troops. It is home to the Army's 1st Cavalry Division and elements of the 4th Infantry Division, as well as the 3rd Armored Cavalry Regiment and the 13th Corps Support Command. It is located near Killeen, Texas.

In June, Fort Hood's commander, Lt. Gen. Rick Lynch, told CNN that he was trying to ease the kind of stresses soldiers face. He has pushed for soldiers working a day schedule to return home for dinner by 6 p.m., and required his personal authorization for anyone working weekends. At the time, two soldiers stationed there had committed suicide in 2009 -- a rate well below those of other posts.